Adsorption of RB-5 Dyestuff onto Boric Acid-Zinc Nanoalloys Isotherm, Kinetic, and Thermodynamic Investigations

In this study, boric acid-zinc (BA-Zn) nanoalloys were employed as an adsorbent for the removal of RB-5 dyestuff from aqueous solutions. The investigation focused on analyzing the impact of the initial dyestuff concentration, solution pH, temperature, and equilibrium contact time on the adsorption process of RB-5. The adsorption behavior of RB-5 onto the surface of BA-Zn-nanoalloys was explored, with a particular emphasis on the influence of initial dyestuff concentration and solution pH. The adsorption equilibrium data were subjected to analysis using Langmuir, Freundlich, DRK, and Temkin isotherm models. The results revealed a consistent alignment of RB-5 adsorption with both Langmuir and Temkin isotherms. Notably, the Langmuir adsorption capacity of BA-Zn-nanoparticles for RB-5 adsorption was determined to be 11.77 mg/g at a temperature of 25°C. In the Temkin isotherm model, an adsorption constant (AT) of 1.003 was obtained. The calculated adsorption energy from the DR adsorption model was 1.09 kJ/mol, implying a physical interaction-driven adsorption process. The empirical data further exhibited conformity with the pseudo-second order kinetic model, reflecting the rate-limiting step and overall kinetics of the adsorption process. Complementary to this, thermodynamic parameters such as enthalpy (ΔH0), Gibbs free energy (ΔG0), and entropy (ΔS0) were evaluated to discern the energetics of BA-Zn-nanoparticle RB-5 adsorption. This study not only underscores the effectiveness of BA-Zn nanoalloys as a potential adsorbent for RB-5 dyestuff removal but also contributes to the understanding of the underlying adsorption mechanisms and energetics. The insights gained hold implications for the development of sustainable and efficient strategies for wastewater treatment and environmental protection.

Hasan İLHAN, Ömer GULER, Tuncay ŞİMŞEK, Salih ALKAN